Analysis of PUGNAc and NAG-thiazoline as Transition State Analogues for Human <i>O</i>-GlcNAcase: Mechanistic and Structural Insights into Inhibitor Selectivity and Transition State Poise
作者:Garrett E. Whitworth、Matthew S. Macauley、Keith A. Stubbs、Rebecca J. Dennis、Edward J. Taylor、Gideon J. Davies、Ian R. Greig、David J. Vocadlo
DOI:10.1021/ja065697o
日期:2007.1.1
PUGNAc and NAG-thiazoline, provide insight into the features of NAG-thiazoline that resemble the transition state and reveal where PUGNAc fails to capture significant binding energy. These studies also point to late transition state poise for the O-GlcNAcase catalyzed reaction with significant nucleophilic participation and little involvement of the leaving group. The potency of NAG-thiazoline, its transition
O-GlcNAcase 催化 β-O-连接的 2-乙酰氨基-2-脱氧-β-d-吡喃葡萄糖苷 (O-GlcNAc) 从翻译后修饰蛋白的丝氨酸和苏氨酸残基中裂解。这种酶的两种有效抑制剂是 O-(2-acetamido-2-deoxy-d-glupyranosylidene)amino-N-phenylcarbamate (PUGNAc) 和 1,2-dideoxy-2'-methyl-alpha-d-glupyranoso[2, 1-d]-Delta2'-噻唑啉(NAG-噻唑啉)。这些抑制剂的衍生物对人 O-GlcNAcase 的选择性与功能相关的人溶酶体 β-己糖胺酶的选择性不同,PUGNAc 衍生物表现出适度的选择性,而 NAG-噻唑啉衍生物表现出高选择性。解决了这种选择性差异的分子基础,以及这些抑制剂模拟 O-GlcNAcase 稳定的过渡态 (TS) 的程度。使用一系列基板,基态 (GS)